At present, there are two types of commonly used coatings for anticorrosion in heat exchangers in China. One type of coating is an organic coating, and most of the domestic brands of heat exchangers on the market currently use these two organic coatings. This coating is mainly achieved by isolating and preventing direct contact of water with the substrate. However, the coating and the body are glued together (physically bonded), and the surface treatment of the substrate is high required , otherwise the coating is prone to peeling, which is the biggest defect of the organic coating.
The heat exchanger heating system has the characteristics of high technical content, long service life. Therefore, the installation quality and after-sales service of the heat exchanger are very important. At the same time, the standard installation is also a problem to be paid attention to after purchasing the heat exchanger. Experts suggest that consumers should not rush to choose small enterprises, small brands without credit guarantees,when purchasing heat exchangers and accessories. Instead, choose strong companies and brand-name products, and do not install them yourself. The place of purchase should be selected at the manufacturer, and installed by a heat exchanger manufacturer or a sales shop professional to ensure that the long-term interests of consumers are not damaged.
The other type is an inorganic coating, represented by zinc-based chromium salts. The coating and the substrate are chemically bonded at a high temperature, and have strong adhesion and are not easily peeled off. However, the process requirements are extremely strict, and the quality of the coating can be ensured by strictly controlling the various process parameters.
In order to save costs, some manufacturers have eliminated some processing links and only do one internal coating treatment. The thickness of the coating generally does not exceed 30 microns. Therefore, many heat exchangers that have been coated on the market currently have a large area of foaming in the hot water for about 5 days, the coating begins to peel off, and the substrate is rusted. Experts remind consumers to be cautious when purchasing anti-corrosion heat exchangers.